Studies On Sulfur Dioxide Insertion Reactions Of Alkenes/Alkynes

Sulfone,as an important structural unit,has good biological activity and is widely found in medicine,pesticides and materials.The traditional synthesis of sulfone compounds requires the use of highly corrosive sulfonating reagents,such as concentrated sulfuric acid and chlorosulfonic acid,as sulfur dioxide sources.Therefore,it is an attractive challenge to develop some green and efficient sulfur dioxide sources to construct sulfone compounds.In addition,free radical tandem reaction is widely used in organic synthesis because of its high efficiency,simplicity,green and other advantages.The main content of this thesis is to use solid sulfur dioxide substitutes such as metasulfite and DABCO·（SO₂）₂ as sulfur dioxide sources to efficiently synthesize sulfone or vinyl sulfone compounds by using free radical tandem reaction and sulfonylation reaction of alkenes/alkynes based on sulfur dioxide insertion strategy.This thesis is mainly divided into the following two parts:Firstly,sulfonylation of alkenes based on the insertion of sulfur dioxide:（1）Sulfonylacetonitriles were synthesized by the reaction of aryldiazonium salt,sodium pyrosulfite and vinyl azide at room temperature without any catalyst or additive.The method used sodium metabisulfite with rich content and low price as the source of sulfur dioxide.The operation was simple and the substrate had good functional group compatibility.In addition,sulfonylacetonitriles compounds synthesized by this method can be further converted into aryl sulfonyl acetamide and tert-butyl（2-tosylethyl）carbamate with antibacterial effect.（2）A copper catalyzed one pot four-component reaction of 1,6-enyne with cyclobutanone oxime ester,DABCO·（SO₂）₂,selenoether was developed.Three new chemical bonds were constructed in high yield,and sulfones containing pyrrolidine skeleton were constructed efficiently.Secondly,sulfonylation of alkynes based on the insertion of sulfur dioxide:（1）Under visible light catalysis,three-component reaction of aryldiazonium salts,DABCO·（SO₂）₂ and dibenzazaalkynes were developed to synthesize vinyl sulfonyldibenzazines with seven membered ring backbone.（2）Copper catalyzed four component reactions of cyclohexanone oxime ester,DABCO·（SO₂）₂,selenoether and alkyne were developed to realize the bifunctionalization of alkyne,and a series of selenium-substituted alkenyl sulfone compounds were synthesized efficiently.The alkenyl sulfone compounds synthesized by this method can be further converted to alkynyl sulfone compounds.In addition,this method has good functional group tolerance and can be used to modify some natural products,such as erlotinib and estrophenol.